Astroblog

Obscured by Clouds. The rough and ready blog of a cloud benighted biologist and amateur astronomer. Astroblog will cover my interests in astronomy, biology and Life, the Universe and Everything.

Saturday, November 12, 2016

A not so Super "Super Moon"

By now everyone has seen the stories that the Full Moon of Monday November 14 is a "Super Moon".

Not just that, a "Super Moon" the likes of which we have not seen since 1948, and will not see again until 2034.

Well, yeah, sort of. Technically, the Moon will be at perigee, when it is closest to the Earth. This is the closest perigee since 1948 (and the next closest will be in 2034).

A full Moon at perigee has been called a
"Super Moon", this is not an astronomical term (the astronomical term is perigee syzygy, but that doesn't trip off the tongue so nicely), but an astrological one first coined in 1979 (see here).

However,astronomical outreach groups started using the term "Super Moon" for perigee Moons and it stuck.

Chart comparing the binocular/telescopic appearance of Novembers Full Perigee Moon with the apogee Moon of April 21. Click to embiggen.

What can you expect to see with the "Super Moon" of November 14?

Not much really, unless you are a regular observer of the Moon, have good visual acuity and a good memory.

The problem is, while the Moon is close this time round, it doesn't actually translate into something you can easily see with your unaided eye. Mondays Full Moon will be around 14% larger and 30% brighter than Aprils apogee Full Moon.

So how's you memory?

If you can remember back that far, and remember seeing the Full Moon in April, you now come up against the limits of human eyesight.

The limit of distances that someone with good vision can distinguish
between is 1 minute of arc (about the width of a human hair). So, for
the vast majority of people any difference smaller than 1 minute of arc
cannot be seen. The difference between the Apogee full Moon of 21 April (29'56") and this Mondays perigee "Super" full Moon (33'55") is around 3 minutes of arc, that is 3 human hair widths, doable for most people, but you do have to remember what the Moon looked like back in April, 8 months ago.

Some of my astronomical friends who are regular Moon viewers can do this. On the other hand I have been trying to image perigee and apogee Moons for a couple of years, and I can never tell the difference.

In contrast, the October 16th Full Moon, which you probably can remember, was 33'45'' wide (compared to this months "Super Moon" of 33'55") so the difference is less than one minute of arc, the Full Moon of 17 September was 33'11" wide, again less than one minute of arc, the Full Moon of 14 December will be 33'40" wide so you will not be able to tell the difference between these full Moons and this Monday's "Super Moon".

Recent perigee Full Moons compared to the 2034 and 1948 perigee full Moons, note that there is only a handful of kilometres between them. (source)

Another twist is that the time of perigee is 11:24 UT, which is 22:24 AEDST, so reasonably later at night. The reason why I emphasis this is that many people will see the Moon rising on the horizon, where it will look bigger due to the Moon illusion and say "I've seen the super Moon" , when no, they haven't, the Moon won't be "super sized" until two hours after it rises.

While all but a few dedicated Moon watchers will be able to see the difference between this "Super Moon" and an apogee Moon, photographing it is another thing entirely. Here are some images of the "Super Moon" of August 2014 that I took. Again, it helps to have images of an apogee Moon to compare with, but you are going to have to wait until 8 June 2017 for your next apogee Moon opportunity.

However, as the Moon is rising it is also increasing in size, so a series of images could capture the size increase towards perigee. However, you WILL need a good zoom lens, binoculars or telescope to capture this, the magnification of an ordinary camera will be insufficient to pick up the size difference.

So, the once in 70 years "Super Moon" will be a little bit disappointing if you are not an obsessive Moon watcher with a good memory, but it will still be a beautiful Full Moon, and if you are handy with a camera and telescope you can capture the Moon as it increases in size, and if you capture next years apogee Moon you can make some nice contrasting images.

still pretty clear, with better comparison stars I estimate it to be magnitude 5.9 (maybe a smidgen brighter). It will be interesting to keep monitoring over the next week to see if it fades or brightens some more.

Astrophiz Podcast 18 is Out

‘The Acceleration of the Expanding Universe’ is beautifully explained
by Dr Brad Tucker. Brad is an Astrophysicist/Cosmologist, and currently
a Research Fellow and PhD supervisor at the Research School of
Astronomy and Astrophysics, Mt. Stromlo Observatory at the Australian
National University.

Dr Nadeshzda Cherbakov Skypes in from Tver in Russia to tell us more about the Cosmic Microwave background Radiation.

In ‘What’s up Doc?’I tell you what to look for in the night
sky this week using the unaided eye, binoculars or telescopes. Oh yes, and I
takes down ’Suuupermoons’

In the news: An update on the SKA, the Square Kilometre Array, our planet’s largest and most sensitive radio telescope

Tuesday, November 08, 2016

The Sky This Week - Thursday November 10 to Thursday November 17

The Full Moon is Monday November 14. This is a Perigee Full Moon, a so-called "Super Moon". There is a "bright" nova in Sagittarius. Venus is prominent in the
evening sky and forms a triangle with Antares and Saturn. On the 12th
Venus is close to the Lagoon Nebula. On the 17 Venus is close to Kaus Borealis, the lid of the "Teapot" of Sagittarius. Mars heads towards Capricornius.

The Full Moon is Monday November 14. This is a Perigee Full Moon, when the Moon is closest to the Earth, a so-called "Super Moon". However, unless you have excellent eyesight and a good memory, you will be unable to distinguish this from any other full Moon.

Evening sky on Saturday November 12 looking west as seen from Adelaide at
21:30 ACDST (around an hour and a half after sunset). Venus is forms a triangle with Antares and Saturn (although they are on the horizon at this time). Venus
is next to the Lagoon Nebula at this time, see iset for a binocular view. The location of Nova Sgr is indicated with a yellow star. Similar
views will be seen throughout Australia at the equivalent local time.
(click
to embiggen).

Venus
continues to rise into darker skies this week. Venus is high in the
dusk sky and can be seen easily from somewhat before half an hour to a
bit after an hour and a half after sunset, staying
visible after twilight is over low above the horizon in truly dark
skies.

Venus starts the week forming a triangle with the pair of Antares and
Saturn. As the week goes on Venus comes closer to the lagoon nebula, being closest on the 12th and 13th. Venus then comes closer to the "teapot" of Sagittarius, and finishes the week close to Kause Borealis, the "lid" of the "teapot".
Venus
is a distinct "gibbous Moon" shape in telescopes.

Nova Sagittarius 2016 has brightened to (just) unaided eye visibility, although the waxing Moon may make it hard to see. located in the "teapot" of Sagittarius viewing instructions and charts are here.

Evening sky on Sunday November 13 looking west as seen from
Adelaide at 22:30ACDST. Mars is in Caprciornius with Venus below brushing the horizon.
Similar views
will be seen elsewhere in Australia at the equivalent local time. (click
to embiggen).

Mars
is in the western evening skies in Capricornius. During
the week Mars moves further through the star poor regions of
Capricornius.

Mars was at opposition on May 22, and is still visibly dimming. It is
no longer a modest telescope object. Mars is visible all evening
long setting after midnight. In even small telescopes Mars will be a
visible, but tiny, gibbous disk, however you are unlikely to see its
markings.

Saturn
was at opposition on the 3rd of June. However, Saturn's change in size
and brightness is nowhere near as spectacular as Mars's. Saturn will be a
reasonable
telescopic object ony for the next few weeks. Saturn is readily visible
next to
Antares in Scorpius. Saturn is still high enough for good telescopic
observation in the
early evening, with only a narrow window for observation, setting abut
10:00 daylight saving time. In even small
telescopes its distinctive rings are obvious.

In the early evening
the line-up of Venus, Saturn and Mars under dark
skies will look very good.

Morning sky on Sunday November 13 looking east as seen from
Adelaide at 5:07 ACDST (an hour before sunrise). Jupiter is low above the horizon but clear in dark skies.

Jupiterrises higher into the morning skies this week. You will need an
unobstructed, level eastern horizon to see it around an hour before
sunrise, but it should be reasonably easy to see by the time of civil twilight half an hour before sunrise.

Mercury is low in the morning twilight but never
rises far above the horizon.

There are lots
of interesting things in the sky to view with a telescope. If you don't have a telescope, now
is a good time to visit one of your local astronomical societies open nights or the local planetariums.

Bright, Unaided Eye Nova in Sagittarius

Western horizon as seen from Adelaide an hour and a half after sunset, the location of the nova is indicated with a yellow star. Similar views will be seen elsewhere in Australia at equivalent local times. Click to embiggen.

High power view, simulating a binocular view of the area around the nova. It is close to a star of similar magnitude. A second nova, visible only in telescopes, is down the bottom of the field. Click to embiggen.

While I was out of commission with colds/flu's two nova exploded in Sagittarius, both near the teapot of Sagittarius. One, PNV J18205200-2822100,has been slowly increasing in brightness and has now broken the unaided eye brightness threshold of magnitude 6.0, with the latest report from New Zealand of 5.4 (clouded out here at the moment). PNV J18205200-2822100 (hereafter Nova Sag 2016) is in the "teapot" of Sagittarius between Kaus Borealis (lambda Sagittarii and Kaus Media (delta Sagittarii) and should be fairly easy to pick up.

Unaided eye nova are not common, so it is well worth going out and having a look, although the waxing Moon may interfere a bit.

Printable black and white chart of the location of PNV J18205200-2822100 (Nov Sag 2016), the large circle is the field of view of 10x 50 binoculars. The star next to Nov Sag 2016 is magnitude 6. Also shown is TCP J18102829-2729590 (Nov Sag 2 2016) Currently magnitude 9 and only visible in telescopes. Click to embiggen and print.

Venus, Antares, Saturn and the Moon (2 and 3 November, 2016)

Venus, Saturn, Antares and the crescent Moon filled with Earth-shine below. Stack of 10 x 10 second 400 ASA Canon IXUS images stacked in Deep Sky Stacker. Imaged on 2 November around 9:00 pm. Click to embiggen to see the stars clearly.

Same setup the following night (3 November). Click to embiggen to see the stars clearly.

Venus has moved up from the spectacular line up of the 28th, and has formed a nice triangle with Saturn and Antares. It was joined by thin crescent Moon on the 2nd and 3rd.

Of course, I was sick as a dog then, I was able to stumble out and take these two shots, before crawling back into bed, and have only now just processed them. They turned out fairly well considering I paid virtually no attention to the process (I had intended to go down the beach and do reflections and artistic stuff before I got sick, but shuffling out to the back yard stretched my capabilities to the limit).

Anyway, do embiggen the images, the extra detail is worth it.

Venus will continue to rise towards the "teapot" of Sagittarius, heading for a meeting with the lagoon nebula this weekend.

This month starts with three bright planets in the evening sky still doing an entrancing planet dance. Venus climbs higher in the evening sky it starts the month close to Antares and Saturn, on the 3rd it is close to the crescent Moon then has some close encounters with bright stars (Kaus Boralis on the 18th) and M22 (on the 19th) in the "teapot" of Sagittarius.

Mars
is close to the Moon, on the 6th. Mars is much diminished and meets the dim globular cluster M75 on the 8th.

Saturn has a close encounter with the Moon on the 2nd and 3rd, then Mercury on the 22nd.

Mercury, returns to the evening sky late in the month and is close to Saturn on the 22nd..

Jupiter
is low in the dawn sky, but is rising over the month, on the 25th
it is not far from the crescent Moon.

Astrophiz Podcast 16 is Out

At the Australian Space Science Conference we talk with Ian
Whitechurch, CEO of Neumann Space, which has just secured a contract to
test their solid state ion space drive on the International Space
Station.

Dr Nadeshzda Cherbakov is back from her dacha and talks from Russia to tell us about Synchrotron Radiation.

In 'What's Up Doc?' I tell you what to look for
up in the sky this week, the ‘blue’ new moon, earthshine,
trans-neptunian object Sedna, Planet 9, how to use Heavens-above and
Calsky to get email alerts for overhead satellites, Iridium flares, the
ISS, comets and novas as they become visible over your own house.

Next Week:We
talk with John Sarkissian, who is the Operations Scientist at the CSIRO
Parkes Radio Observatory. It’s a sensational interview. In two weeks:We
talk about the accelerating universe controversy with the Mt Stromlo
Research Fellow, Cosmologist and Type Ia Supernovae researcher Dr Brad
Tucker.

Tuesday, November 01, 2016

The Sky This Week - Thursday November 3 to Thursday November 10

The First Quarter Moon is Tuesday November 8. Venus is prominent in the evening sky and forms a triangle with Antares and Saturn. On November 5 Venus is close to the star theta Ophiuchi. The crescent Moon is close to Mars on November 6th. Mars heads towards Capricornius and is close to a faint globular cluster on the 8th.

The First Quarter Moon is Tuesday November 8.

Evening sky on Saturday November 5 looking west as seen from Adelaide at 20:45 ACDST. Venus is forms a triangle with Antares and Saturn. Venus is almost on top of theta Ophiuchi at this time. Similar
views will be seen throughout Australia at the equivalent local time. Viewing times for the ISS can be found here (click
to embiggen).

Venus
continues to rise into darker skies this week. Venus is high in the dusk sky and can be seen easily from somewhat before half an hour to a bit after an hour and a half after sunset, staying
visible after twilight is over low above the horizon in truly dark skies.

Venus starts the week forming a triangle with the pair of Antares and Saturn with the crescent Moon close by. This will be a lovely sight, especially later in the evening when earth-shine fills the dark part of the crescent Moon.

As the week goes on Venus and the Moon rise higher in the sky. On November 5 Venus is close to the star theta Ophiuchi. To the unaided eye theta Ophiuchi will be overwhelmed by the brightness of Venus. Venus is a distinct "gibbous Moon" shape in telescopes.

Evening sky on Sunday November 6 looking west as seen from
Adelaide at 21:45 ACDST. Mars is close to the
crescent Moon with Venus below and Saturn brushing the horizon.
Similar views
will be seen elsewhere in Australia at the equivalent local time. (click
to embiggen).

Mars
is in the western evening skies on the borders of Capricornius. During the week Mars moves further towards the star poor regions of
Capricornius.

Mars was at opposition on May 22, and is still visibly dimming. It is no longer a modest telescope object. Mars is visible all evening
long setting after midnight. In even small telescopes Mars will be a visible, but tiny, gibbous disk, however you are unlikely to see its markings.

On November 6 the crescent is Moon close to Mars. On November 7-8; Mars is close to to the dim globular cluster M75. This is a telescope only event.

Saturn
was at opposition on the 3rd of June. However, Saturn's change in size and brightness is nowhere near as spectacular as Mars's. Saturn will be a reasonable
telescopic object ony for the next few weeks. Saturn is readily visible next to
Antares in Scorpius. Saturn is still high enough for good telescopic
observation in the
early evening, with only anarrow window for observation, setting abut 10:00 daylight saving time. In even small
telescopes its distinctive rings are obvious.

In the early evening
the line-up of Venus, Saturn and Mars under dark
skies will look very good.

Morning sky on Friday October 28 looking east as seen from
Adelaide at 5:45 ACDST. Jupiter is low in the twilight glow .

Jupiteremerges from the twilight into the morning skies this week. You will need an
unobstructed, level eastern horizon to see it around half an hour before
sunrise.

Mercury is low in the morning twilight but never
rises far above the horizon.

There are lots
of interesting things in the sky to view with a telescope. If you don't have a telescope, now
is a good time to visit one of your local astronomical societies open nights or the local planetariums.